The new processors jump into 3GHz territory, ranging from 3.06 or 3.2GHz Core i3 or 3.6GHz Core i5 options on the 21.5 inch model (each with 4MB of L3 cache), or a 3.2GHz Core i3 or 2.6GHz Core i5 (both with 4MB of L3 cache) or a Quad Core 2.8GHz i5 or Quad Core 2.93GHz Core i7 (both with 8MB of L3 cache) on the 27 inch model.

Previous Core i5 and i7 iMacs were clocked at 2.8GHz or below, but still outpaced the 3.33GHz Core 2 Duo, thanks to the Nehalem QuickPath memory architecture, which includes a direct memory controller on the CPU rather than having the processor talk to RAM via its external chipset. Quad Cores and more onboard CPU cache RAM also speed up the performance of the chips independent of their clock rate.

The new Nehalem microarchitecture also ends Apple's former strategy of using NVIDIA's integrated 9400M across the board to provide its Macs with both standard chipset functions (such as providing a memory controller, SATA, USB, PCIe, audio, and networking functions) and graphics features.

All of the new iMac models offer ATI Radeon HD dedicated graphics processors:

Comparable Windows PCs often pack on even more graphics RAM. For example, Acer's similarly equipped Gateway One supplies the same ATI Radeon HD 4670 with 1GB of dedicated graphics RAM. This primarily benefits video games, as it allows the game to load texture maps and other data into graphics RAM for optimal performance. Apple's iMacs are designed more to be digital media hubs running iLife and other creative apps, which aren't as hungry for graphics RAM. The company still touts video game play on its iMac systems, but hardcore gamers are not likely to be shopping for Macs given that most games are tied to Windows. However, the iMac's new options for 512MB or 1GB of graphics RAM should help out users who plan to run Windows PC games natively using Boot Camp.

Base models of the iMac ship with 1TB 7200 RPM SATA hard drives and offer an identical 2TB upgrade option (apart from the entry level 21.5 inch model, which ships with a 500GB hard drive). All models also ship with 4GB of RAM, expandable to an officially supported 16GB (8GB on the 21.5 inch models). Prices are unchanged from the previous models, and range from $1199 or $1499 for the 21.5 inch iMac to $1699 or $1999 for the 27 inch model.

CPU upgrades cost a $200 premium, the video card bump costs $150, while the 2TB disk upgrade has dropped from a pricy $250 option to a more reasonable $150. Both models provide four RAM slots, giving users the option to upgrade incrementally without having to throw away RAM to make room for new parts.

The iMac's expansion potential positions it clearly ahead of the compact, entry level Mac mini, which is now easier to access but still offers little potential for serious future upgrades. The Mac Pro continues to deliver even greater upgrade options, with room for 4 hard drives; dual optical drives; two six-core processors; a double-wide, 16-lane PCI Express 2.0 graphics slot and two 4-lane PCI Express 2.0 slots; up to 32GB of installed RAM; and additional Ethernet and FireWire 800 ports. Of course, the Mac Pro is also significantly more expensive even without a display.

The new processors jump into 3GHz territory, ranging from 3.06, 3.2 or 3.6GHz Core i3 options on the 21.5 inch model (each with 4MB of L3 cache), or a 3.2GHz Core i3 or 2.6GHz Core i5 (both with 4MB of L3 cache) or a Quad Core 2.8GHz i5 or Quad Core 2.93GHz Core i7 (both with 8MB of L3 cache) on the 27 inch model.

Nice review, but this information is incorrect. There is no 3.6GHz Core i3 option on any iMac. The 21.5" models can be had with 3.06 or 3.2 GHz Core i3 or a 3.6GHz Core i5. Similarly there is no 2.6GHz Core i5 on the 27" model, but the same 3.6GHz Core i5 that is offered on the 21.5". Just figured someone should point this out.

So it's confirmed... Apple is not going to write graphic drivers for Snow Leopard - just add new hardware instead of making existing hardware functional. So much for SL ever being used in any creative environment.
How Apple can be content with their flagship OS being a disaster is beyond me???

Same hardware on windows side is 70% faster for those who don't know.

For those who would defend SL... Some of us need to do more then browse the web & check email.

So it's confirmed... Apple is not going to write graphic drivers for Snow Leopard - just add new hardware instead of making existing hardware functional. So much for SL ever being used in any creative environment.
How Apple can be content with their flagship OS being a disaster is beyond me???

Confirmed? Based on what?

Snow Leopard 'a disaster'? Based on what?

The facts are that SL is probably the best OS on the planet for general purpose use. It's not perfect, but its problems are minor.

Even so, Apple continues to update it and makes improvements all the time. They frequently improve graphics drivers in 10.x.x updates.

SL will never be used in any creative environment? That's just plain laughable. Tell at the graphics artist and other media creators that and watch how hard they laugh.

I'm curious how the second (1 TB) hard disk mounts in the Finder, if it's intended to be a 'Users' repository. Ideally it would use the 'mount' command in such a way that it integrates seamlessly into the file hierarchy, rather than as a separate disk icon.

Also, there are some applications that won't work properly if not installed on the same disk as the system itself. (Lame but true.) That means that people can't install them in their own home directory if it resides on a physically separate disk. Has Apple addressed any of this with these new (except for the Mac Pros) multi-disk machines?